The son of Mark Harris—a North Carolina Republican still fighting for an undecided House seat in the state’s Ninth District—testified Wednesday that he repeatedly warned his father that one of his hired operatives, McCrae Dowless, could be engaging in election fraud.

The district has been mired in controversy since the 2018 midterms, when allegations surfaced that Dowless illegally paid volunteers to pick up absentee ballots to help Harris win. It remains unclear if any of the ballots were tampered with, and Harris currently leads democratic rival Dan McCready by 905 votes.